diff options
Diffstat (limited to 'mrbgems/mruby-enum-ext/mrblib/enum.rb')
| -rw-r--r-- | mrbgems/mruby-enum-ext/mrblib/enum.rb | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/mrbgems/mruby-enum-ext/mrblib/enum.rb b/mrbgems/mruby-enum-ext/mrblib/enum.rb new file mode 100644 index 000000000..a9545da98 --- /dev/null +++ b/mrbgems/mruby-enum-ext/mrblib/enum.rb @@ -0,0 +1,85 @@ +## +# Enumerable +# +module Enumerable + ## + # call-seq: + # enum.drop(n) -> array + # + # Drops first n elements from <i>enum</i>, and returns rest elements + # in an array. + # + # a = [1, 2, 3, 4, 5, 0] + # a.drop(3) #=> [4, 5, 0] + + def drop(n) + raise TypeError, "expected Integer for 1st argument" unless n.kind_of? Integer + raise ArgumentError, "attempt to drop negative size" if n < 0 + + ary = [] + self.each {|e| n == 0 ? ary << e : n -= 1 } + ary + end + + ## + # call-seq: + # enum.drop_while {|arr| block } -> array + # + # Drops elements up to, but not including, the first element for + # which the block returns +nil+ or +false+ and returns an array + # containing the remaining elements. + # + # a = [1, 2, 3, 4, 5, 0] + # a.drop_while {|i| i < 3 } #=> [3, 4, 5, 0] + + def drop_while(&block) + ary, state = [], false + self.each do |e| + state = true if !state and !block.call(e) + ary << e if state + end + ary + end + + ## + # call-seq: + # enum.take(n) -> array + # + # Returns first n elements from <i>enum</i>. + # + # a = [1, 2, 3, 4, 5, 0] + # a.take(3) #=> [1, 2, 3] + + def take(n) + raise TypeError, "expected Integer for 1st argument" unless n.kind_of? Integer + raise ArgumentError, "attempt to take negative size" if n < 0 + + ary = [] + self.each do |e| + break if ary.size >= n + ary << e + end + ary + end + + ## + # call-seq: + # enum.take_while {|arr| block } -> array + # + # Passes elements to the block until the block returns +nil+ or +false+, + # then stops iterating and returns an array of all prior elements. + # + # + # a = [1, 2, 3, 4, 5, 0] + # a.take_while {|i| i < 3 } #=> [1, 2] + + def take_while(&block) + ary = [] + self.each do |e| + return ary unless block.call(e) + ary << e + end + ary + end + +end |
